Building on the significant advances made during the first six years of this: Center, the overarching themes of our current Center focus on: mechanisms, response to intervention and developmental course and outcome, in both Learning Disabilities (LD), particularly Reading Disability (RD) and Attention Deficit/Hyperactivity Disorder (ADHD). In this Center we exploit functional magnetic resonance imaging (fMRI) to examine neurobiological mechanisms, specifically, the functional organization of linguistic processes in children and young adults with a range of reading abilities and disabilities (including RD and hyperlexia). Project I uses fMRI to begin to examine the neural basis of attentional processes in ADHD, to determine the neurobiological "signature" for ADHD; the same cohort is studied in Project II using event related potentials (ERPs). Project IV examines the functional organization of brain in children with RD, before, during and after a highly focused phonological intervention. In Project V we use fMRI to study phonological and semantic processing in a group of hyperlexics. Finally, in Project III, the availability of an epidemiologic sample followed longitudinally with yearly measures of reading, offers an unprecedented opportunity to link neural mechanisms of reading ability and disability in children to the developmental course and longterm outcome of reading from kindergarten through young adulthood. In Project III, we use fMRI to study the neurologic residua of childhood RD in both compensated and persistently poor readers.